Overexpression of Arabidopsis Translationally Controlled Tumor Protein Gene AtTCTP Enhances Drought Tolerance with Rapid ABA-Induced Stomatal Closure

Abstract

Translationally controlled tumor protein (TCTP), also termed P23 in human, belongs to a family of calcium-and tubulin-binding proteins, and it is generally regarded as a growth-regulating protein. Recently, Arabidopsis TCTP (AtTCTP) has been reported to function as an important growth regulator in plants. On the other hand, plant TCTP has been suggested to be involved in abiotic stress signaling such as aluminum, salt, and water deficit by a number of microarray or proteomic analyses. In this study, the biological functions of AtTCTP were investigated by using transgenic Arabidopsis plants overexpressing AtTCTP. Interestingly, AtTCTP overexpression enhanced drought tolerance in plants. The expression analysis showed that AtTCTP was expressed in guard cells as well as in actively growing tissues. Physiological studies of the overexpression lines showed increased ABA-and calcium-induced stomatal closure ratios and faster stomatal closing responses to ABA. Furthermore, in vitro protein-protein interaction analysis confirmed the interaction between AtTCTP and microtubules, and microtubule cosedimentation assays revealed that the microtubule binding of AtTCTP increased after calcium treatment. These results demonstrate that the overexpression of AtTCTP confers drought tolerance to plants by rapid ABA-mediated stomatal closure via the interaction with microtubules in which calcium binding enhances the interaction. Collectively, the present results suggest that the plant TCTP has molecular properties similar to animal TCTPs, such as tubulin-and calciumbinding, and that it functions in ABA-mediated stomatal movement, in addition to regulating the growth of plants.

The Translational Controlled Tumour Protein TCTP: Biological Functions and Regulation

“…TCTP from the rubber tree (Hevea brasiliensis) was found to be regulated by drought, low temperature, high salt, ethylene, hydrogen peroxide or wounding (Deng et al 2016;Li et al 2013). This is consistent with the observation that overexpression of TCTP in Arabidopsis resulted in increased drought tolerance of the plants (Kim et al 2012a). Moreover, in the cabbage (Brassica oleracea), TCTP was found to be involved in maintaining tolerance to heat, cold and to salt stresses (Cao et al 2010).…”

“…In this function, the Arabidopsis and Drosophila proteins are exchangeable in their respective systems (Brioudes et al 2010). The microtubule-binding activity of AtTCTP has been investigated in yet another paper (Kim et al 2012a); the binding to actin filaments (Bazile et al 2009) and identification of an actin-binding site (Tsarova et al 2011) were also reported for TCTP.…”

Characterization of the pumpkin Translationally-Controlled Tumor ProteinCmTCTP

“…12 More recently, a role in stomatal closure and thus response to water deficit has been shown for AtTCTP1. 13 Pumpkin TCTP has been isolated from phloem and found to interact with CmPP16 and suggested to be necessary for its phloem root-ward transport. 14 The isolation of a TCTP mRNA homolog from Lupinus phloem sap exudates indicates that this gene may also function in a non-cell autonomous fashion in plants as well.…”

Proteomic Analysis of Microtubule Interacting Proteins over the Course of Xylem Tracheary Element Formation in Arabidopsis

“…These include wellestablished MAPs such as MAP65-1 and MAP65-2 (Smertenko et Mao et al, 2005), seven kinesins (two family 14) (Reddy and Day, 2001;Lee and Liu, 2004;Zhu and Dixit, 2012), AIR9 (Buschmann et al, 2006), and AIM1 (Chuong et al, 2002). Other candidate MAPs based on bibliographical cross-referencing (Supplemental Data Set 3) included MAP190/EMB1579 (Igarashi et al, 2000), seven dynamin-related proteins (Maeda et al, 1992;Hong et al, 2003;Hamada et al, 2006), PLD (Gardiner et al, 2001), CSI1 (Bringmann et al, 2012;Li et al, 2012;Mei et al, 2012), TCTP (Kim et al, 2012), and THO2 (Hamada et al, 2009). Proteins associated with the posttranslational modification of microtubules Color-coded heat map shows the hierarchical clustering of subsets of proteins with distinct accumulation profiles during TE differentiation, expressed as log 2 -fold ratio (relative to t 0 h).…”